how to make piezoelectric mobile phone charger circuit ?

how to make piezoelectric mobile phone charger circuit

Development of The Project:
The power generating soles are one of my first concept projects. I started my first prototype last five years ago although it was a very primitive, compared to my current design. My old prototype had two TO-3 plastic spacer sandwiched between two piezo discs. It produces a fair amount of current, enough to charge a Nokia 3310.


5 years later, I came back with the idea of using the sandwiched piezo setup, this time integrated to a charge collector and powerbank. So I thought, why not add 2 more pairs? After all, more is better.

Concept Behind The Project:
Piezoelectricity was present ever since mid-18th century. Piezoelectricity is the electric charge that accumulates in certain solid materials (such as crystals, certain ceramics in response to applied mechanical stress. This sounds familiar! Yes they do, you can actually find those piezo elements in your old/ outdated earphones from the 90's.

Why Not Use Dynamos?
As much as possible, I tried to avoid using dynamos. Yes dynamos produce more electricity but it will feel like you've stuffed a rock in your shoe. Don't forget dynamos will create a lot of noise.

Any Practical Uses?
As funny as it sounds, charging a phone with your shoe isn't really joke. Who knows maybe someday shoe companies like Nike could use these insole generators to power fitness chips (inside shoes) that would sync to your phone wirelessly. This way, you don't have to charge your smart-shoes just to sync them with your phone.

Four years ago, we first heard about how Korean scientists had proposed using sound to charge mobile phones. They explained that it could be done via a piezoelectric effect, in which zinc oxide nanowires converted sound-caused vibrations into electricity. At the time, the researchers couldn't generate enough of a current to actually charge a phone. Now, however, scientists from Nokia and Queen Mary University of London (QMUL) have succeeded in doing so.

Like the Korean team, the Nokia/QMUL researchers utilized zinc oxide, in the form of a sheet of tiny nanorods. As is the case with other piezoelectric materials, zinc oxide produces an electrical current when subjected to mechanical stress. The nanorods will actually bend in response to sound waves, creating that stress in the process.

The scientists started by spraying a coating of liquid zinc oxide onto a plastic sheet. That sheet was then placed in a "mixture of chemicals" and heated to 90ºC (194ºF), which caused the zinc oxide to grow into an array of nanorods.

In order to harvest the voltage generated, the nanorod sheet was sandwiched between two electrical contact sheets. Whereas these contacts would typically be made from gold, the researchers developed a cost-cutting technique that allowed them to use ordinary aluminum foil instead.

The prototype energy-harvesting device is about the size of a Nokia Lumina 925, and is reportedly capable of generating up to five volts using "everyday background noise" such as traffic, music and voices. Five volts is enough to charge a mobile phone, and is significantly higher than the 50 millivolts managed in the previous effort.

"Being able to keep mobile devices working for longer, or do away with batteries completely by tapping into the stray energy that is all around us is an exciting concept," said QMUL's Dr. Joe Briscoe. "We hope that we have brought this technology closer to viability."